Electrical System

Question 1

The aircraft engine driven(IDG) and APU generators are rated at?

Answer 1

40 KVA

Question 2

The engine driven (IDG) generators have an

Overload rating of?

Answer 2

45 KVA for 5 minutes

60 KVA for 5 seconds

Question 3

The main aircraft generators supply power to how many AC buses?

Answer 3

4

Question 4

Power for the 28v DC systems is supplied by?

Answer 4

4 TRU’s

(Transformer Rectifier Units)

Question 5

The APU battery is rated at?

Answer 5

24v and 43 amp hours

Question 6

The main battery is rated at?

Answer 6

24v and 17 amp hours

Question 7

TRU 1 normally supplies which bus?

Answer 7

DC BUS 1

Question 8

TRU 2 normally supplies ?

Answer 8

DC Bus 2 and DC UTIL Bus

Question 9

ESS TRU 1 and ESS TRU 2 normally supplies?

Answer 9

DC ESS BUS

Question 10

The ADG supplies AC power to?

Answer 10

1. 3B hydraulic pump
2. ESS AC BUS
3. Slats/Flaps
4. Pitch Trim

Question 11

The Main battery is kept in a charged condition by a charger that is powered from which bus?

Answer 11

AC Bus 1

Question 12

The APU battery is kept in a charged condition by a charger that is powered from which bus?

Answer 12

AC Service Bus

Question 13

The IDG provides a means of converting

Answer 13

variable engine speed to a contant generator speed of 12,000 rpm

Question 14

Fault protection for each generator is provided by?

Answer 14

Generator Control Units (GCU’s)

Question 15

The priority for allowing power to AC Bus 1 would be?

Answer 15

1. Gen 1
2. APU
3. Gen 2
4. External AC

Question 16

IDG 2(GEN 2) normally powers:

Answer 16

• AC Bus 2
• Service Bus

Question 17

Each TRU is rated for how much current?

Answer 17

120 amps

Question 18

Which DC Bus ties have automatic operation?

Answer 18

• MAIN TIE
• CROSS TIE
• ESS TIE
• TRU CONTACTOR CONTROL
• ESS TRU TRANSFER

Question 19

The ADG will auto deploy when?

Answer 19

• AC Bus 1 and AC Bus 2 falls below 50 volts
• weight on wheels system indicates aircraft is airborne
• Any aircraft generators were online for at least 3.45 seconds prior to the loss of power on AC Buses 1 and 2

Question 20

An Amber IDG fault light / caution light indicates?

Answer 20

• Low IDG oil pressure and / or high IDG oil temp

Question 21

An AUTO XFER fail light(amber) on the Electrical panel indicates:

Answer 21

Generator over current or a bus fault

Question 22

An AC ESS XFER light(white) on the Electrical panel indicates:

Answer 22

AC Bus 1 is no longer powering the AC ESSENTIAL Bus

Question 23

What happens when you switch on the DC SERVICE switch?

Answer 23

• With no AC power, the SERV BUS is powered directly from the APU BATT DIR BUS via the service bus contactor
• SERVICE CONFIGURATION message appears on DC synoptic page
• Service bus contactor not represented on the DC synoptic page

Question 24

What happens when you turn on the Battery Master switch?

Answer 24

• Connects the main battery to the battery bus through the main battery direct bus
• Connects the APU battery to the battery bus throught the APU battery direct bus

Question 25

With the Battery Master switch left on, is there anything you should be concerned about?

Answer 25

* Yes, the CRT displays have a 5 minute limitation of being left on without the AC system providing power to the cooling fans * You can run down the Main and APU batteries if left on too long

Question 26

How many DC buses does the CRJ have?

Answer 26

9 buses in total DC EMER BUS not shown

Question 27

What happens when TRU 1 fails?

Answer 27

* Main Tie contactor automatically closes * TRU 2 powers DC BUS 1 * DC UTIL BUS is load shed(turned off) * Status Messages saying TRU 1 has failed and Main Tie has closed

Question 28

What happens when TRU 1 and TRU 2 fail?

Answer 28

* DC MAIN TIE and CROSS TIE automatically close * ESS TRU 2 powers DC BUS 1, DC BUS 2 and DC SERV BUS * DC UTIL BUS is unpowered * Status messages saying MAIN and Cross TIE's have closed and TRU 1, 2 failed

Question 29

What happens when ESS TRU 1 fails?

Answer 29

* DC ESS TIE automatically closes allowing ESS TRU 2 to power the DC ESS BUS * DC ESS TIE CLSD status message displayed

Question 30

Which DC Bus Tie does not have automatic operation?

Answer 30

Service Bus Contactor * It gets activated by the DC SERVICE switch on the Overhead when there is no AC power on the airplane

Question 31

What are the nine DC buses?

Answer 31

* DC Bus 1 * DC Bus 2 * DC ESS Bus * DC SERV Bus * DC UTIL Bus * DC BATT Bus * MAIN BATT DIR Bus * APU BATT DIR Bus * DC EMER Bus